U.S. patent application number 09/841523 was filed with the patent office on 2001-10-25 for multi-functional vibration actuator.
This patent application is currently assigned to Tokin Corporation. Invention is credited to Sakai, Nobuyasu.
Application Number | 20010033215 09/841523 |
Document ID | / |
Family ID | 18634033 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010033215 |
Kind Code |
A1 |
Sakai, Nobuyasu |
October 25, 2001 |
Multi-functional vibration actuator
Abstract
A multi-functional vibration actuator comprises a magnetic
circuit flexibly supported by a suspension fixed to the magnetic
circuit, a coil arranged at a gap of the magnetic circuit, and a
vibration transmitting portion. The coil includes at least two
coils. One of the coils is a main coil. Another coil is an
auxiliary coil. Even if the coil jumps out of the uniform magnetic
flux distribution of a magnetic pole gap during movement, a uniform
magnetic flux is always applied of the coil.
Inventors: |
Sakai, Nobuyasu;
(Sendai-shi, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN &
LANGER & CHICK, PC
767 THIRD AVENUE
25TH AVE
NEW YORK
NY
10017-2023
US
|
Assignee: |
Tokin Corporation
7-1, Koriyama 6-chome Taihaku-ku, Sendai-shi
Miyagi
JP
|
Family ID: |
18634033 |
Appl. No.: |
09/841523 |
Filed: |
April 24, 2001 |
Current U.S.
Class: |
335/252 |
Current CPC
Class: |
H04R 2400/03 20130101;
H04R 9/063 20130101; H04R 2400/07 20130101; B06B 1/045
20130101 |
Class at
Publication: |
335/252 |
International
Class: |
H01F 007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 25, 2000 |
JP |
123798/2000 |
Claims
What is claimed is:
1. A multi-functional vibration actuator comprising a magnetic
circuit flexibly supported by a suspension fixed to a vibration
transmitting portion, a coil arranged at a gap of the magnetic
circuit, and the vibration transmitting portion, wherein the coil
comprises at least two coils.
2. The multi-functional vibration actuator according to claim 1,
wherein the coil has at least one auxiliary coil so as to apply a
uniform magnetic flux to the coil even when the coil jumps out of a
uniform magnetic flux distribution range of a magnetic pole gap
during driving.
3. The multi-functional vibration actuator according to claim 1,
wherein the coil is fixed to a vibrating member; the vibrating
member has a recess at a random location in a diameter direction;
and the coil is inserted to the recess or fixed to a top face of a
projection formed by the recess.
4. The multi-functional vibration actuator according to claim 1,
wherein at least two coils are different in at least one of a wire
diameter and a wire material.
5. The multi-functional vibration actuator according to claim 1,
wherein at least two coils are connected in series or in parallel
with two terminals or three terminals.
6. The multi-functional vibration actuator according to claim 1,
wherein the coil has a coil wire wound densely at the side of the
vibrating member to which the coi is fixed.
7. The multi-functional vibration actuator according to claim 1,
wherein the magnetic circuit and the coil fixed to the vibrating
member interact with each other to operate at an opposite
phase.
8. The multi-functional vibration actuator according to claim 1,
wherein said at least two coils are formed by a magnetic gradient
by differentiating winding width at random height.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a multi-functional
vibration actuator that is mostly mounted on a mobile communication
apparatus, such as a mobile telephone, and functions to generate a
ringing tone, a speech sound, and vibration.
[0003] 2. Description of the Related Art
[0004] Conventional multi-functional vibration actuators have a
magnetic circuit composed of a yoke, a permanent magnet and a
plate. The magnetic circuit is flexibly supported by a circular and
spiral plate spring suspension that is fixed to the periphery of
the yoke of the magnetic circuit and a vibration transmitting
portion.
[0005] A coil includes one normally wound coil and is arranged at a
gap of the magnetic circuit. The coil is fixed to U-shape parts
provided at random locations in the diameter direction of the
vibrating member. A coil wire of the coil is spread over a face of
the vibrating member in various shapes without providing negative
effects on the vibration of the vibrating member. The wire is
attached to random locations of the vibrating member with an
elastic material, such as adhesive provided in dots, and is
soldered to a terminal board. In the similar manner to the
suspension, the vibrating member is fixed to the vibration
transmitting portion.
[0006] In such a multi-functional vibration actuator, when driving
current is supplied to the coil, the magnetic circuit or the coil
moves up and down in an axial direction. The vibration transmitting
portion becomes a fixed part at low frequencies, and an elastic
member at high frequencies, vibrating as a part of the vibrating
member. In a vibration mode, the magnetic circuit and the coil
fixed to the vibrating member interact with each other and operate
at an opposite phase, transmitting vibrations to the outside.
[0007] In the conventional multi-functional vibration actuator, the
single normally wound coil as the coil is bonded at a random
location in the diameter direction of the vibrating member, is
inserted to a recess provided at the vibrating member, and is
bonded to the top face of a projection formed by a recess, or the
like. However, when the coil jumps out of a uniform magnetic flux
distribution of a magnetic pole gap to the outside of a magnetic
pole during driving, driving force decreases and follow-up
properties become insignificant. Accordingly, electric current with
respect to driving force becomes nonlinear, losing sound distortion
characteristics as an electroacoustic transducer.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
provide a multi-functional vibration actuator. Even when the coil
jumps out of a uniform magnetic flux distribution of a magnetic
pole gap, the vibration actuator has a small decrease in driving
force and maintains sufficient coil follow-up properties. The
vibration actuator also hardly causes the nonlinearity of electric
current with respect to driving force, and does not lose sound
distortion characteristics as an electroacoustic transducer.
[0009] In order to solve the problems mentioned above, according to
the present invention, there is provided a multi-functional
vibration actuator in which a coil has a plurality of coils. At
least one distortion-improving auxiliary coil is mounted on a main
coil, so that a uniform magnetic flux is applied to the coil even
when the coil jumps out of the uniform distribution of a magnetic
pole gap during driving. Or alternately, the coil is repeatedly
non-densely and densely wound at random heights (number of lines),
and winding widths (number of layers) are differentiated to add
magnetic gradient. Thus, even when the coil jumps out of the
uniform magnetic flux distribution of a magnetic pole gap during
movement, a uniform magnetic flux is always applied on the
coil.
[0010] In the multi-functional vibration actuator, a vibrating
member has a recess at a random location in the diameter direction
thereof. The coil is inserted to the recess or fixed to the top
face of a projection formed by the recess. The coil has the same or
different wire diameters, wire materials and so forth. The coil is
wound densely at the side of the vibrating member to which the coil
is fixed. A coil wire is connected in series or in rows with two
terminals or three terminals.
[0011] Specifically, in a multi-functional vibration actuator in
which a magnetic circuit is flexibly supported by a suspension
fixed to the vibration transmitting portion, the coil arranged at a
gap of the magnetic circuit, and the magnetic circuit, and the coil
includes at least two coils.
[0012] At least one auxiliary coil may be mounted so as to provide
a uniform magnetic flux even when the coil jumps out of the uniform
magnetic flux distribution range of a magnetic pole gap during
driving.
[0013] Moreover, in a multi-functional vibration actuator in which
a magnetic circuit is flexibly supported by a suspension fixed to
the vibration transmitting portion, the coil arranged at a gap of
the magnetic circuit, and the magnetic circuit, the coil has a
magnetic gradient by differentiating winding widths at random
heights.
[0014] The coil may be fixed to the vibrating member. The vibrating
member may have a recess at a random location in the diameter
direction thereof. The coil may be inserted to the recess or fixed
to the top face of a projection formed by the recess.
[0015] The coil may be one or more in number. Each coil may be made
of the same or different wire diameter, wire material, and so
forth.
[0016] A coil wire may be connected in series or in parallel with
two terminals or three terminals.
[0017] The coil wire of the coil may be wound densely at the side
of the vibrating member to which the coil is fixed.
[0018] The magnetic circuit and the coil fixed to the vibrating
member may interact with each other to operate in an opposite
phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a cross-sectional view of a conventional
multi-functional vibration actuator;
[0020] FIG. 2 is a cross-sectional view of normally wound coils in
the conventional multi-functional vibration actuator;
[0021] FIG. 3A is an arrangement diagram of a coil in a vibrating
member of the conventional multi-functional vibration actuator,
showing that the coil is fixed to the top face of a projection
formed by a recess of the vibrating member;
[0022] FIG. 3B is a diagram, showing that the coil is fixed to the
recess of the vibrating member;
[0023] FIG. 4 is a cross-sectional view of a multi-functional
vibration actuator according to an embodiment of the present
invention;
[0024] FIG. 5A is an arrangement diagram of a coil in the vibrating
member of the multi-functional vibration actuator of the present
invention, showing that a main coil is inserted to a recess of the
vibrating member and an auxiliary coil is also fixed to the top
plane of a projection formed by the recess of the vibrating
member;
[0025] FIG. 5B is an arrangement diagram of a coil in the vibrating
member of the multi-functional vibration actuator of the present
invention, showing that an auxiliary coil and a main coil are
sequentially inserted into a recess of the vibrating member in the
vibrating direction thereof at the side of a magnetic circuit and
at the side of the vibrating member, respectively;
[0026] FIG. 5C is an arrangement diagram of a coil in the vibrating
member of the multi-functional vibration actuator of the present
invention, showing that a main coil and an auxiliary coil are
provided in a recess of the vibrating member parallel to the
vibrating direction thereof;
[0027] FIG. 6A is a diagram of connecting coils in the
multi-functional vibration actuator of the present invention,
showing that the coils are connected in series;
[0028] FIG. 6B is a diagram of connecting coils in the
multi-functional vibration actuator of the present invention,
showing that the coils are connected in parallel;
[0029] FIG. 6C is a diagram of connecting coils in the
multi-functional vibration actuator of the present invention,
showing that the coils are connected in series and terminals lead
out from a node;
[0030] FIG. 7A is another arrangement diagram of coils in the
vibrating member of the multi-functional vibration actuator of the
present invention, showing that two auxiliary coils are wound at
both ends in the height direction of normally wound coils;
[0031] FIG. 7B is another arrangement diagram of coils in the
vibrating member of the multi-functional vibration actuator of the
present invention, showing that the coils are densely wound with a
coil at the side of the vibrating member and with another auxiliary
coil at the opposite side thereof;
[0032] FIG. 7C is another arrangement diagram of coils in the
vibrating member of the multi-functional vibration actuator of the
present invention, showing that normally wound coils are further
wound with an auxiliary coil at the side of the vibrating member;
and
[0033] FIG. 7D is another arrangement diagram of coils in the
vibrating member of the multi-functional vibration actuator of the
present invention, showing that the coils are densely wound with a
coil at the side of the vibrating member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] First, a conventional multi-functional vibration actuator
will be explained by referring to FIGS. 1 to 3 in order to make the
present invention easily understood prior to the explanation of the
embodiments of the present invention.
[0035] As shown in FIG. 1, a magnetic circuit is composed of a yoke
11, a permanent magnet 13 and a plate 15 and is flexibly supported
by a suspension 19 which is a circular spiral plate spring fixed to
a vibration transmitting portion 17, in a conventional
multi-functional vibration actuator 9. The suspension 19 is fixed
to the periphery of the yoke 11 of the magnetic circuit and to the
vibration transmitting portion 17.
[0036] A coil 25 are fixed with an adhesive or the like to U-shape
parts 23 of a vibrating member 61 provided at random locations in
the diameter direction of the vibrating member 61 and are arranged
at the gaps of the magnetic circuit. A coil wire 27 is spread over
the face of the vibrating member 61 in a V shape, U shape, bellows
shape or the combination thereof without providing negative effects
on the vibration of the vibrating member 61. The coil wire 27 is
attached with an elastic material, such as adhesive provided in
dots at random locations of the vibrating member 61, and is fixed
to a terminal board 29 with solder 31.
[0037] For the coil 25, one normally wound coil is used as shown in
FIG. 2. The coil 25 is arranged as shown in FIG. 1 or FIGS. 3A and
3B.
[0038] The vibrating member 61 is fixed to the vibration
transmitting portion 17 like the suspension 19. When driving
current is sent into the coil 25, the magnetic circuit or the coil
25 repeatedly move up and down in an axial direction. The vibration
transmitting portion 17 becomes a fixed part at low frequencies,
and an elastic member at high frequencies, vibrating as a part of
the vibrating member 61. At a vibration mode, the magnetic circuit
and the coil 25 fixed to the vibrating member 61 interact with each
other to operate at an opposite phase, transmitting vibrations to
the outside.
[0039] A first cover 33 and a second cover 35 are fixed to the
vibration transmitting portion 17 so as to protect a functional
part. The first cover 33 has one or more sound emitting holes 37 of
a random diameter for air viscous damping action. A center axis 39
is inserted through a center hole of the magnetic circuit.
[0040] Subsequently, the multi-functional actuator of the
embodiments of the present invention will be explained by referring
to FIGS. 4 to 7.
EXAMPLE 1
[0041] In reference to FIG. 4, a multi-functional vibration
actuator 51 of Example 1 of the present invention has a magnetic
circuit in which the disc-shape permanent magnet 13 is sandwiched
with the yoke 11 and the plate 15, and has an internal magnetic
structure.
[0042] The center axis 39 in a bolt or pin shape is inserted
through the center hole of the magnetic circuit, coaxially
positioning the yoke 11, the permanent magnet 13 and the plate 15
and is fixed by caulking. After coaxially positioning the yoke 11,
the permanent magnet 13 and the plate 15, the center axis 39 may be
removed. The components of the magnetic circuit are fixed by the
attraction of the permanent magnet 13 or by both the attraction and
an adhesive or by caulking and so forth.
[0043] The suspension 53 is composed of one circular spiral plate
spring, flexibly supporting the magnetic circuit. The suspension 53
is fixed to the periphery of the yoke 11 with an elastic material
55, such as a tackiness agent, an adhesive or resin, caulking or
the like. The other end thereof is fixed to the vibration
transmitting portion 17. On the other hand, the coil has coils 57
and 59 which are fixed with adhesive or the like to highly reliable
U-shaped parts 63 at random locations of the vibrating member 61
from which the coils 57 and 59 are unlikely to fall off. The coils
57 and 59 are arranged in the gap of the magnetic circuit.
[0044] A coil wire 65 is spread over the face of the vibrating
member 61 in a V shape, U shape, bellows shape or the combination
thereof without providing negative effects on the vibration of the
vibrating member 61. The coil wire 65 is attached with an elastic
material such as adhesive provided in dots at random locations of
the vibrating member 61. Accordingly, unstable operations at an
acoustic mode are prohibited, reducing distortion components and
preventing disconnection, caused by driving input voltage and long
driving or the like. Furthermore, the coil wire 65 is connected to
the terminal board 29 of a terminal block 41 provided at the
periphery of the vibration transmitting portion 17 with the solder
31, and is covered with a protective agent 43 to protect the coil
wire 65 and a connection part.
[0045] Moreover, by fixing the suspension 53 to the periphery of
the yoke 11, the magnetic circuit is prevented from rocking. In
order to prevent the magnetic circuit from contacting the vibrating
member 61 because of excess amplitude from drop shock or the like,
a stopper 45 is provided at the inner circumference of the
vibration transmitting portion 17. One or more stoppers 45 are
provided over the entire inner circumference.
[0046] At a vibration mode of the multi-functional vibration
actuator of the present invention, the magnetic circuit and coils
57 and 59 that are fixed to the vibrating member 61, operate at an
opposite phase due to mutual attraction and repulsion. Thus, a gap
between the magnetic circuit or the suspension 53 and the vibrating
member 61 is made larger than a gap between the magnetic circuit
and the first cover 33 in consideration of the amplitude of the
magnetic circuit and the vibrating member 61. Accordingly, the
vibrating member 61 is prevented from contacting the magnetic
circuit or the suspension 53.
[0047] In addition to the internal magnetic structure shown in the
multi-functional vibration actuator of FIG. 4, the magnetic circuit
may have the external magnetic or radial structure. Additionally,
in case of either the internal magnetic structure or the external
magnetic structure, the tips of the yoke 11 of the magnetic circuit
are in the shape of protruding, projecting, recessed or the like so
as to easily generate a high magnetic flux density. The magnetic
pole of the permanent magnet 13 may face either direction. The
suspension 53 is in one body with the vibration transmitting
portion 17 by insert molding, welding, bonding, or the like.
[0048] Herein, the vibrating member 61 is in the shape of a flat,
saucer, curved surface, corrugation or the combination thereof at a
random plate thickness. In case of the curved surface, the
curvature thereof is single or the combination of various
curvatures, and furthermore, a random curvature to increase the
rigidity of the vibrating member 61 at the inside of the coils 57
and 59 and to minimize high harmonic distortion components. Thus,
at the vibration mode, the vibrating member 61 is prevented from
contacting the magnetic circuit or the suspension 53. At the
acoustic mode, predetermined acoustic characteristics may be
obtained. The vibrating member 61 is formed of at least one plastic
film material selected from the group consisting of polyether imide
(PEI), polyethylene terephthalate (PET), polycarbonate (PC),
polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI) and
aramid (PPTA).
[0049] Moreover, the periphery of the vibrating member 61 is
coaxially mounted to the vibration transmitting portion 17 through
an elastic material such as a tackiness agent, an adhesive and
resin if necessary, so as to provide a larger amplitude of the
vibrating member 61. The vibration transmitting portion 17 is made
of resin or the like to provide elasticity.
[0050] The vibration transmitting portion 17 has the first cover 33
and the second cover 35 as protection for a functional part that
provides vibrations. The first cover 33, fixed to the vibration
transmitting portion 17, has one or more sound radiating holes 37
of a random diameter for air viscous damping action in order to
prohibit the nonlinear unstable operations of the vibrating member
61 and to reduce high harmonic distortion components around
resonance. The cover 33 is in the form of a circle, ellipse, flat
oval, polygon or the combination thereof. It is also necessary to
give attention to preventing air in-flow and outflow from anywhere
besides the sound emitting holes 37 for air viscous damping
action.
[0051] In the multi-functional vibration actuator of FIG. 4, the
arrangement of a plurality of coils is shown as a first embodiment
of a coil arrangement. In FIG. 4, the main coils 57 and the
auxiliary coils 59 for correcting distortions are arranged in a
vibrating direction at the side of the vibrating member 61 and at
the side of the magnetic circuit, respectively. The coils are
bonded to the vibrating member 61 with adhesive or the like in a
bobbin form.
EXAMPLE 2
[0052] Referring to FIG. 5A, in the multi-functional vibration
actuator of Example 2 according to the present invention, a coil
has a main coil 57 and an auxiliary coil 59. The main coil 57 is
inserted into a recess 67 provided at a random location in the
diameter direction of the vibrating member 61. Furthermore, the
auxiliary coil 59 for correcting distortions is fixed with adhesive
or the like to the top face of a projection formed by the recess 67
of the vibrating member 61.
[0053] Moreover, as shown in FIG. 5B, the auxiliary coil 59 for
correcting distortion and the main coil 57 are inserted into the
recess 67 in the vibrating direction of the vibrating member 61 at
the side of the magnetic circuit and at the side of the vibrating
member 61, respectively. Between the auxiliary coil 59 and the main
coil 57, a projection 69 is provided at the recess 67.
[0054] Referring to FIG. 5C, the main coil 57 and the auxiliary
coil 59 for correcting distortion are provided at the recess 67 of
the vibrating member 61 parallel to the vibrating direction
thereof.
[0055] Each coil is made of the same or different wire diameter,
wire materials and so forth.
[0056] As described in reference to FIGS. 1 to 3, the single coils
25 are used in the conventional multi-functional vibration
actuator.
[0057] In an electroacoustic transducer, magnetic gaps and the
clearance of the coils 25 are necessary to provide stable
operations of the coils 25 in a magnetic field. However, in the
multi-functional vibration actuator in which a magnetic circuit is
held with the suspension 53 and which generates vibrations by the
vibration of the magnetic circuit during low frequency application,
the coils 25 cannot operate accurately in accordance with applied
signals. Thus, nonlinear vibrations are generated, and distortion
characteristics become insignificant.
[0058] Accordingly, in the present invention shown in FIGS. 4 and
5, the auxiliary coils 59 for correcting distortions are added to
the conventional coils (main coils) 57 to form the coil. Thus, even
when the coils move out of a uniform magnetic flux distribution
away from a magnetic gap, the auxiliary coils 59 function as
distortion-improving coils. Thus, by raising the magnetic flux
sensitivity of the coils as a whole, the coils may operate
accurately in accordance with applied signals, and preferable
distortion characteristics may be obtained.
[0059] Moreover, each method shown in FIGS. 6A to 6C may be applied
as the method of connecting wires.
[0060] In reference to FIG. 6A, coils 71, 73 and 75 are connected
in series.
[0061] In FIG. 6B, the coils 71, 73 and 75 are connected in
parallel.
[0062] Moreover, in reference to FIG. 6C, the coils 71 and 73 are
connected in series, and terminals lead out from a node.
EXAMPLE 3
[0063] A coil arrangement of the multi-functional vibration
actuator of Example 3 according to the present invention will be
explained.
[0064] As shown in FIG. 7A, a coil has the coil 57 and the
auxiliary coil 59 wound in a certain way to have functions. At both
ends in the height direction of the normally wound a coil (a) to
act as the coil 57, two coils (b, c) to act as the coils 59 and 77
are wound.
[0065] As shown in FIG. 7B, the end at the side of the vibrating
member 61 is densely wound with the coil (a) act as the coil 57,
and the other end is wound with another coil (b) to act as the coil
59.
[0066] As shown in FIG. 7C, the normally wound coil (a) as the coil
57 is further wound with the coil (b) as the coil 59 at the side of
the vibrating member 61.
[0067] Furthermore, as shown in FIG. 7D, the end at the side of the
vibrating member 61 is densely wound with the coil (a) to form the
coil 57 and the coil 59.
[0068] Herein, each coil, as shown in FIGS. 7A to 7D, is repeatedly
non-densely and densely wound at random heights, i.e. number of
lines, to differentiate winding widths, i.e. number of layers, and
to add magnetic gradient. Thus, even when a moving coil jumps out
of a uniform magnetic flux distribution of a magnetic pole gap, a
uniform magnetic flux is always applied to at least one coil.
[0069] In this case, one or more coils are provided. The wire
diameter, wire material and the like of each coil are the same or
different from each other. When they are the same, coils are easily
manufactured. When they are different, the characteristics of coils
are easily designed, which is advantageous.
[0070] By simply winding coils in various ways without changing the
shapes of coil installing parts of the vibrating member 61 as
illustrated above, the decline in driving force is prevented and
follow-up properties are kept even outside of a magnetic pole
during driving. The nonlinearity of electric current with respect
to driving force is also prohibited, so that no distortions are
found.
[0071] When driving current is applied to the coils 57, 59, and 77,
a magnetic circuit vibrates as the circuit is flexibly supported by
the vibrating member 61 fixed to the vibration transmitting portion
17 and by the suspension 53. At this time, the vibration
transmitting portion 17 becomes a solid part at low frequencies and
an elastic member at high frequencies, and vibrates as a part of
the vibrating member 61. The magnetic circuit and the coils 57, 59,
and 77 fixed to the vibrating member 61 work at an opposite phase
due to mutual attraction and repulsion. With the coils shown in
FIGS. 4, 5A, 5B, 5C and 7A, 7B, 7C, 7D, the decrease in driving
force may be prevented. Follow-up properties may be kept. The
nonlinearity of electric current with respect to driving force may
also be prohibited. Thus, distortion components may be reduced.
[0072] As described above, the present invention provides the
multi-functional vibration actuator in which auxiliary coils for
correcting distortions are provided to conventional single coils.
Thus, the auxiliary coils work as distortion-improving coils even
when the coils move out of a uniform magnetic flux distribution
away from a magnetic gap. By raising the magnetic flux sensitivity
of the coils as a whole, the decrease in driving force may be
prevented and follow-up properties may be maintained. The
nonlinearity of current with respect to driving force may also be
prohibited. Accordingly, distortion components may be reduced.
Additionally, the same results as mentioned above are obtained by
repeatedly winding coils non-densely and densely at random heights,
i.e. number of lines, differentiating winding widths, i.e. number
of layers, and adding magnetic gradient to provide a uniform
magnetic flux even during driving.
* * * * *